As a backlight device that irradiates a display panel for displaying an image with light, there is a direct type backlight device in which light emitting diodes (LEDs), cold-cathode tubes, or the like are disposed at positions facing one plane of the display panel (for example, see Japanese Patent Application Laid-Open No. 2005-276716). In addition, as another backlight device, there is an edge light type backlight device that includes: a light guide plate; and a light source disposed at a position facing an end face of the light guide plate, the light guide plate irradiating a display panel from one plane the light guide plate with light entering the end face from the light source.
Currently, as a display apparatus including a display panel and a backlight device that irradiates the display panel with light, a thin type display apparatus whit a narrowed frame is required. As a conventional edge light type backlight device included in such a display apparatus, there is a backlight device that includes: a cover body that covering the light source and a circumferential part of one plane of the light guide plate on the light source side; and an optical sheet disposed on a side opposite to one side of the cover body on which the light guide plate is disposed. The cover body is provided to prevent from irradiating the display panel with light directly from the light source.
In such a conventional backlight device, light enters the end face of the light guide plate from the light source and the light guide plate irradiates the display panel from one plane of the light guide plate with the light through the optical sheet.